firmware: cs_dsp: add driver to support firmware loading on Cirrus Logic DSPs

firmware: cs_dsp: add driver to support firmware loading on Cirrus Logic DSPs

wm_adsp originally provided firmware loading on some audio DSP and was
implemented as an ASoC codec driver. However, the firmware loading now
covers a wider range of DSP cores and peripherals containing them,
beyond just audio. So it needs to be available to non-audio drivers. All
the core firmware loading support has been moved into a new driver
cs_dsp, leaving only the ASoC-specific parts in wm_adsp.

Signed-off-by: Simon Trimmer <simont@opensource.cirrus.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20210913160057.103842-17-simont@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>